The Turkish government has followed through on a threat to block YouTube from within its borders.

The action, which comes a week after the country blocked Twitter, was "another desperate and depressing move by Turkey," according to Neelie Kroes, vice president of the European Commission.

It began on Thursday in reaction to the posting of a conversation apparently between Turkey's foreign minister, intelligence chief and a senior member of the armed forces that concerned a possible or theoretical attack against militants in neighboring Syria.

"It's like the first wave of the Twitter blocking that happened last week," said Doug Madory at Internet monitoring company Renesys. The company said several of its remote systems in the country were unable to access the Google-run website several hours after Turkey's telecommunications authority said it would block the site.

Twitter was blocked after the micro-blogging service was used to spread links to a video that appears to implicate Turkish Prime Minister Recep Tayyip Erdogan in a corruption scandal.

It began with blocking the site through DNS (domain name system), the servers that translate the youtube.com domain name to the numeric Internet address used by computers to communicate. When Turkish users figured out they could sidestep the DNS restrictions by switching to use Google's DNS service, the government moved to block access to that.

Thursday's blocking of YouTube appears to working the same way with restrictions being placed on the DNS entry for the site, said Doug Madory at Renesys.

Google DNS has since become available again in Turkey but Twitter remains blocked, said Madory.

The government is now blocking Twitter's IP addresses and users have resorted to VPN (virtual private network) connections to get around that restriction.